(DEFUN C:DDLINES ()
  (SETQ LINE_PTLST NIL)
  (SETQ LINES_SS (SSGET '((0 . "line"))))
  (SETQ LINES_SSLEN (SSLENGTH LINES_SS))
  (SETQ LINES_CNT 0)
  (WHILE (< LINES_CNT LINES_SSLEN)
    (SETQ THIS_LINE (ENTGET (SSNAME LINES_SS LINES_CNT)))
    (IF (OR (MEMBER (LIST (CONS 10 (CDR (ASSOC 10 THIS_LINE)))(CONS 11 (CDR (ASSOC 11 THIS_LINE)))) LINE_PTLST)
            (MEMBER (LIST (CONS 10 (CDR (ASSOC 11 THIS_LINE)))(CONS 11 (CDR (ASSOC 10 THIS_LINE)))) LINE_PTLST)
        )
        (ENTDEL (SSNAME LINES_SS LINES_CNT))
        (SETQ LINE_PTLST (APPEND LINE_PTLST (LIST (LIST (ASSOC 10 THIS_LINE)(ASSOC 11 THIS_LINE)))))
    )
    (SETQ LINES_CNT (1+ LINES_CNT))
    (IF (EQ (REM LINES_CNT 1000) 0)
      (PROGN
        (PRINC (STRCAT "\010\010\010\010\010\010\010" (ITOA LINES_CNT)))
        (PRINC)
      )
    )
  )
)